﻿/*
 * SonarAnalyzer for .NET
 * Copyright (C) 2014-2025 SonarSource Sàrl
 * mailto:info AT sonarsource DOT com
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the Sonar Source-Available License Version 1, as published by SonarSource SA.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the Sonar Source-Available License for more details.
 *
 * You should have received a copy of the Sonar Source-Available License
 * along with this program; if not, see https://sonarsource.com/license/ssal/
 */

namespace SonarAnalyzer.VisualBasic.Rules;

[DiagnosticAnalyzer(LanguageNames.VisualBasic)]
public sealed class VariableUnused : VariableUnusedBase
{
    private static readonly DiagnosticDescriptor Rule = DescriptorFactory.Create(DiagnosticId, MessageFormat);

    public override ImmutableArray<DiagnosticDescriptor> SupportedDiagnostics { get; } = ImmutableArray.Create(Rule);

    protected override void Initialize(SonarAnalysisContext context) =>
        context.RegisterCodeBlockStartAction(cbc =>
        {
            var collector = new UnusedLocalsCollector();

            cbc.RegisterNodeAction(collector.CollectDeclarations, SyntaxKind.LocalDeclarationStatement);
            cbc.RegisterNodeAction(collector.CollectUsages, SyntaxKind.IdentifierName);
            cbc.RegisterCodeBlockEndAction(c => collector.ReportUnusedVariables(c, Rule));
        });

    private class UnusedLocalsCollector : UnusedLocalsCollectorBase<LocalDeclarationStatementSyntax>
    {
        protected override IEnumerable<SyntaxNode> GetDeclaredVariables(LocalDeclarationStatementSyntax localDeclaration) =>
            localDeclaration.Declarators.SelectMany(x => x.Names);
    }
}
